SPONGES OR PORIFERA 



27 



Fig. 3; RED SPONGE, Long 

 Island Sound. 



much decomposed, and then it is washed in the water to remove all 

 of the fleshy parts, leaving only the tough, horny sl^eleton, which 

 may be bleached in weak hydrochloric acid and hyposulphite of 



soda. 



Sponges grow best on hard bottoms where there is a consider- 

 able current to bring food, and to pro- 

 vide them with an abundance of aerated 

 water. In Florida there are fiv^e varie- 

 ties of sponges called " sheepswool," 

 "yellow," "grass," "velvet" and "glove 

 sponges." 



The Sheepswool Sponges, (Spongia 

 equina gossypina,), are most valuable, 

 the fishery being worth about S 250,000 

 annually. The fibrous skeleton is very 

 tough and fine meshed, and the inter- 

 ior of the sponge is cavernous while 

 the outer surface is covered with woolly 



looking tufts of fibres. This is the common large bath sponge. 



The Yellow Sponge, (Spongia agari- 

 cinaj, lacks the woolly tufts characteris- 

 tic of the sheepswool, and its surface is apt 

 to be fairly even, with numerous pit-like 

 pores. The fishery is woi'th about $15,- 

 000 annually. 



The Grass Sponge, (Spongia grami- 

 neaj, has the shape of a truncated cone 

 the broad end being uppermost. The up- 

 per surface contains all of the large open- 

 ings and is usually depressed, giving the 

 sponge a cup-shape. The sides are furrowed with numerous small 

 openings between the ridges. The fishery is worth about $20,000 

 annually. 



In the Velvet Sponge, (Spongia equina ineandriformis,), the 

 surface is apt to show winding channels bordered by flat ridges of 

 fibre. The least valuable is the Glove Sponge (Spongia officinalis 

 tuhidifera, Figs. 1, 2), in which the surface is quite even with dense 

 fibres which project outward in fine tufts. The sponge is lasually 



Fig. 4; RED SPONGE, Long 

 Island Sound. 



